diff --git a/libraries/AP_NavEKF2/AP_NavEKF2.cpp b/libraries/AP_NavEKF2/AP_NavEKF2.cpp
index 9f7f461e0a..8d72d9a114 100644
--- a/libraries/AP_NavEKF2/AP_NavEKF2.cpp
+++ b/libraries/AP_NavEKF2/AP_NavEKF2.cpp
@@ -204,6 +204,7 @@ const AP_Param::GroupInfo NavEKF2::var_info[] = {
     // @Description: This parameter controls the primary height sensor used by the EKF. If the selected option cannot be used, it will default to Baro as the primary height source. Setting 0 will use the baro altitude at all times. Setting 1 uses the range finder and is only available in combination with optical flow navigation (EK2_GPS_TYPE = 3). Setting 2 uses GPS. Setting 3 uses the range beacon data. NOTE - the EK2_RNG_USE_HGT parameter can be used to switch to range-finder when close to the ground.
     // @Values: 0:Use Baro, 1:Use Range Finder, 2:Use GPS, 3:Use Range Beacon
     // @User: Advanced
+    // @RebootRequired: True
     AP_GROUPINFO("ALT_SOURCE", 9, NavEKF2, _altSource, 0),
 
     // @Param: ALT_M_NSE